The Example of the Sickle-Cell Allele Demonstrates a Key Aspect

question 21

Multiple Choice

The example of the sickle-cell allele demonstrates a key aspect of evolution through natural selection,in that

• A) adaptation and fitness are in relation to the individual organism, not the general population.
• B) human populations in the tropics are the most susceptible to random changes caused by natural selection.
• C) natural selection increases the variety in a population upon which subsequent natural selective processes can act.
• D) adaptation and fitness are in relation to specific environments; traits are not universally adaptive or maladaptive.
• E) although natural selection usually acts upon the phenotype, it can sometimes act upon the genotype.

---

Definitions:

Null Hypothesis

The hypothesis in statistical analysis that proposes there is no significant difference or relationship between specified populations, any observed difference being due to sampling or experimental error.

Distribution

A statistical term describing the way values of a variable are spread or dispersed across a range.

Significance Level

A threshold chosen by the researcher to denote the probability below which a result is considered statistically significant, indicating that the observed result would be unlikely under the null hypothesis.

Kruskal-Wallis Test

A nonparametric statistical test used to compare three or more groups on a continuous or ordinal outcome without assuming a normal distribution among the groups.